Demonstration of an optical-coherence converter

Studying the coherence of an optical field is typically compartmentalized with respect to its different optical degrees of freedom (DoFs) -- spatial, temporal, and polarization. Although this traditional approach succeeds when the DoFs are uncoupled, it fails at capturing key features of the field's coherence if the DOFs are indeed correlated -- a situation that arises often. By viewing coherence as a `resource' that can be shared among the DoFs, it becomes possible to convert the entropy associated with the fluctuations in one DoF to another DoF that is initially fluctuation-free. Here, we verify experimentally that coherence can indeed be reversibly exchanged -- without loss of energy -- between polarization and the spatial DoF of a partially coherent field. Starting from a linearly polarized spatially incoherent field -- one that produces no spatial interference fringes -- we obtain a spatially coherent field that is unpolarized. By reallocating the entropy to polarization, the field becomes invariant with regards to the action of a polarization scrambler, thus suggesting a strategy for avoiding the deleterious effects of a randomizing system on a DoF of the optical field.Comment: 7 pages; 6 figure

Cast report: Intrauterine Retention of Fetal Bones: An Unusual Cause of Infertility

Couples presenting with infertility face peculiar sociocultural problems, these are especially evident in African countries where a very high premium is placed on children and childbearing.We report a case of a 30-year-old nullipara with a 3-year history of secondary infertility who on investigation was found to have fetal bones from an earlier incomplete abortion. She achieved pregnancy within three months of endoscopic removal of the fetal bones. Keywords: Intrauterine bone fragments, Secondary infertility, Foreign body, Termination of pregnanc

Anaesthetic Agent Usage and Wastage during Caesarean Deliveries Done with Spinal Anaesthesia in a Labour Ward Theatre: A Concern for the Financial Implication

Background: Local anaesthesia usage and wastage are common in the operation rooms. The wastage is often not given due considerations. Budgetary allocation for drugs is an identifiable area for cost-cutting and savings. Hence, the need to minimize wastageObjectives: To assess and estimate the amount of local anaesthesia usage and wastage in the labour ward theatre. Also, to analyze the financial implications of the wastages and suggest appropriate steps to reduce the wastages.Methodology: A prospective observational study conducted in the labour ward theatre of a tertiary care hospital. The amount of local anaesthesia administered to the patient during spinal anaesthesia prior to caesarean section was considered the dose used. The wastage was considered as the amount of local anaesthetic agents left unutilized in the syringes, ampules or vials after completion of each caesarean delivery. An estimation of the cost of wasted local anaesthetic agents was made.Result: The local anaesthetic agents being used in significant quantities were hyperbaric bupivacaine, plain lidocaine and lidocaine with adrenaline. The wastage was found more during the use of hyperbaric bupivacaine as the cost of its wastage formed the bulk (N75,000.00/ $210.10) of the estimated total cost of wasted local anaesthetic agents during the study period which was N88, 100.00 ($246.77).Conclusion: There were appropriate uses of the local anaesthesia with respect to the choice and doses for caesarean deliveries but there were wastages often ignored as infinitesimal. In the long run, the wastages become significant and the financial implication scale up the burden of health bills. Effective waste reduction strategies have input in the overall reduction of financial burden associated with health care. Emphasis should be t ailored towards awareness of these wastages among resident doctors and their prudent use of local anaesthesia. Key words: Cost, Lignocaine, Waste, Theatre

Efficacy of zinc supplementation for the treatment of dysmenorrhoea: a double-blind randomised controlled trial

Objectives To determine the efficacy of zinc sulfate supplementation in managing dysmenorrhoea. Methods In total, 103 high school students were randomised into an experimental arm (52 students) and a control arm (51 students) and received 40-mg zinc sulfate or placebo, respectively, over three cycles. Primary outcome measures were the mean Visual Analogue Scale score, which measured pain over three cycles, and the frequency of nausea and vomiting. Secondary outcomes were the use of additional analgesics and the frequency of allergic reactions. Results Fifty participants were analysed in each group. Mean pain scores were not significantly different between the groups before administering zinc sulfate therapy. Following the intervention, the mean pain scores for the treatment (2.80 ± 2.28) and placebo (3.48 ± 2.85) groups were not significantly different in the first cycle; however, scores in the treatment group were significantly better in the second (2.56 ± 1.97 vs 3.80 ± 2.77) and third (1.95 ± 1.72 vs 3.95 ± 2.82) cycles. No significant differences were observed between the groups in the nausea and vomiting incidence and the requirement for additional analgesics. Conclusions Zinc sulfate reduces dysmenorrhoea severity with minimal or no adverse effects, especially with more than one cycle of usage. Trial Registration Number: PACTR202105843292338. The trial is publicly available and was registered at www.pactr.org on 25 May 2021